Pugliese layered bake of rice, potatoes, and mussels is a one-dish mediterranean masterpiece. This high protein family meal is fresh, coastal, and captures southern Italy's resourceful cooking spirit.
Preheat the oven to 400°F (200°C). Rinse and scrub the mussels; discard any that are open.
Slice potatoes very thinly and soak in cold water for 10 minutes to remove excess starch, then drain thoroughly.
Lightly grease a 9x13-inch baking dish with olive oil. Layer half the potato slices on the bottom, then season with a little salt and pepper.
Scatter half the sliced onions and cherry tomatoes over potatoes. Sprinkle half the garlic, parsley, and a third of the pecorino cheese on top.
Spread half the uncooked rice evenly over the vegetables. Open each mussel and place them (shell-on or out, as preferred) across the rice layer.
Repeat layers: remaining potatoes, salt/pepper, onions, tomatoes, garlic, parsley, remaining rice, and most of the cheese, reserving some for the top.
Pour reserved mussel juice and enough water to just cover the rice and potatoes (about 2 - 2.5 cups liquid total). Drizzle with olive oil.
Cover tightly with foil and bake in the center rack for 40 minutes. Remove foil, add remaining cheese, and bake uncovered an additional 10-15 minutes until the top is golden and liquid is absorbed.
Let rest 10 minutes before serving to help flavors settle and ease cutting. Serve warm, ensuring each portion has mussels, rice, and potatoes.